Interchangeable mask assembly

ABSTRACT

A system of breathing arrangements for delivering breathable gas to a patient includes at least first and second cushion components, e.g., full-face, nasal, nasal prongs, nose tip, and/or a combination of any of the above, including a nasal or full-face cushion and nasal prongs/nozzles combination, etc., that are different from one another in at least one aspect, and a common frame assembly configured to support each of the first and second cushion components. Various embodiments are directed to a full-face or nasal mask used with a frame having lateral connector portions having a stiffening member. The mask assembly may include a nose height adjustment device for the height of the cushion, or a cushion adjustment member by which the position of the cushion may be adjusted relative to the frame. The mask assembly may include a chin strap assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/216,115, filed Dec. 11, 2018, which is a continuation of U.S. patent application Ser. No. 15/841,488, filed Dec. 14, 2017, now U.S. Pat. No. 10,183,138, which is a continuation of U.S. patent application Ser. No. 14/289,158, filed May 28, 2014, now U.S. Pat. No. 9,962,510, which is a continuation of U.S. patent application Ser. No. 12/083,779, filed Jan. 6, 2009, which is the U.S. national phase of International Application No. PCT/AU2006/001570, filed Oct. 24, 2006 which designated the U.S. and claims the benefit of U.S. Provisional Application No. 60/729,746, filed Oct. 25, 2005, each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a nasal assembly used for treatment, e.g., of Sleep Disordered Breathing (SDB) with Continuous Positive Airway Pressure (CPAP) or Non-Invasive Positive Pressure Ventilation (NPPV).

BACKGROUND OF THE INVENTION

Interfaces, such as a nasal mask assembly, for use with blowers and flow generators in the treatment of sleep disordered breathing (SDB) typically include a soft-face contacting portion, such as a cushion, and a rigid shell or frame. In use, the interface is held in a sealing position by headgear so as to enable a supply of air at positive pressure (e.g. 2-30 cm H₂O) to be delivered to the user's or patient's or user's airways.

One factor in the efficacy of therapy and compliance of patients with therapy is the comfort and fit of the patient interface. It has been necessary to design a wide variety of masks to best treat and/or suit the user's needs. While there are a large number of patient interfaces, typically each cushion has been specially designed to be used with only a single frame, headgear, etc.

Puritan Bennett includes a mask commercially sold under the name of Breeze® that allows a cushion sold under the name of DreamSeal® to be retrofit to it. Further details of such mask are disclosed at the website http://www.puritanbennett.com/prod/Product.aspx?S1=SPT&S2=&id=233.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention is to provide a mask assembly including at least one main component that can be used with a variety of different styles or types of mask assemblies.

In one embodiment of the invention, there is provided a system of breathing arrangements for delivering breathable gas to a patient, comprising at least first and second cushion components that are different from one another in at least one aspect, and a common frame assembly configured to support each of the first and second cushion components.

In another embodiment of the invention, there is provided a mask assembly for a user comprising a frame having a main body and lateral connector portions; and a cushion component provided to the frame and defining a breathing cavity configured to accommodate at least a portion of the user's nose in use, said cushion component including a face contacting seal portion adapted to sealingly engage with at least a portion of the user's nose in use, said cushion component having an aperture to communicate pressurized gas from the breathing chamber to the user's airways in use, and a main wall portion, opposite from the aperture, extending upwardly away from the frame, said main wall portion including a stiffening portion.

In another embodiment of the invention, there is provided a mask assembly for a user comprising a frame having a main body and lateral connector portions; and a cushion component provided to the frame and defining a breathing cavity configured to accommodate at least a portion of the user's nose in use, said cushion component including a face contacting seal portion adapted to sealingly engage with at least a portion of the user's nose in use, said cushion component having an aperture to communicate pressurized gas from the breathing chamber to the user's airways in use, and a main wall portion, opposite from the aperture, extending upwardly away from the frame, said frame being configured for positioning beneath the nose and between the user's upper lip and nose in use.

In another embodiment of the invention, a mask assembly for a user comprising a frame having a main body and lateral connector portions; a cushion component provided to the frame and defining a breathing cavity configured to accommodate at least a portion of the user's nose in use, said cushion component including a face contacting seal portion adapted to sealingly engage with at least a portion of the user's nose in use, said cushion component having an aperture to communicate pressurized gas from the breathing chamber to the user's airways in use, and a main wall portion, opposite from the aperture, extending upwardly away from the frame, said cushion having an upper portion and a lower portion, wherein at least the upper portion includes a nose height adjusting member.

In another embodiment of the invention, there is provided a mask assembly for a user comprising a frame; a cushion component provided to the frame and defining a breathing cavity configured to accommodate at least a portion of the user's nose in use, said cushion component including a face contacting seal portion adapted to sealingly engage with at least a portion of the user's nose in use, said cushion component having an aperture to communicate pressurized gas from the breathing chamber to the user's airways in use, and a main wall portion, opposite from the aperture, extending upwardly away from the frame; and a frame adjustment member to adjust the position of the cushion component relative to the frame.

In another embodiment of the invention, there is provided a mask assembly for a user comprising a frame; a cushion component provided to the frame and defining a breathing cavity configured to accommodate at least a portion of the user's nose in use, said cushion component including a face contacting seal portion adapted to sealingly engage with at least a portion of the user's nose in use, said cushion component having an aperture to communicate pressurized gas from the breathing chamber to the user's airways in use and a main wall portion, opposite from the aperture, extending upwardly away from the frame; and a chin strap assembly including an extension member provided to each side of the frame and a chin strap having a main chin support portion and straps coupled to the extension members.

In another embodiment of the invention, there is provided a mask assembly for a user comprising a common frame; a cushion component provided to the frame and including a pair of nasal prongs or nozzles adapted to engage the user's nares in use; and a supplemental cushion component in the form of a nasal cushion or a full-face cushion, wherein the cushion component and the supplemental cushion component cooperatively seal with the user's face in use.

These and other aspects of the invention will be described in or apparent from the following detailed description of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described in relation to the following figures, in which:

FIG. 1 is a schematic view of a mask assembly according to an embodiment of the present invention;

FIGS. 2-13 are views of a mask assembly according to another embodiment of the present invention;

FIG. 14 is a perspective view of a mask assembly according to another embodiment of the present invention;

FIGS. 15-16 are views of a mask assembly according to yet another embodiment of the present invention;

FIGS. 17-19 are views of a portion of a mask assembly according to still another embodiment of the present invention;

FIG. 20 is a perspective view of a mask assembly according to another embodiment of the present invention;

FIG. 21 is a perspective view of a mask assembly according to another embodiment of the present invention;

FIG. 22 is a perspective view of a mask assembly according to another embodiment of the present invention;

FIG. 23 is a perspective view of a mask assembly according to another embodiment of the present invention;

FIG. 24 is a perspective view of a mask assembly according to another embodiment of the present invention;

FIGS. 25-26 are views of a mask assembly according to another embodiment of the present invention; and

FIGS. 27-31 are views of a mask assembly according to still another embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The following description is provided in relation to several embodiments which may share common characteristics and/or features. It is understood that one or more features of any one embodiment may be combinable with one or more features of the other embodiments which combinations form additional embodiments.

1.0 First Embodiment—Common Frame with Activa™ or UltraMirage™ Cushion Component

FIG. 1 illustrates an interchangeable mask system 5 according to an embodiment of the present invention. Mask system includes a common frame component 10, one of two cushion components 15, 20, one of two elbow components 25, 30, and headgear 35. The mask system is intended for use in positive pressure therapy for users with obstructive sleep apnea (OSA) or another respiratory disorder.

The common frame 10 has a main body 40 defining a central opening 45. Main body 40 includes at least two lateral arms 50, each of which can be coupled to a headgear strap 55 of headgear. The straps may be connected to the frame using a press-fit connector 60, as is known in the art. Common frame 10 may also include a forehead support 65 that has a bridge 70 provided with forehead pads 75 to rest against the user's forehead in use. Forehead support may be adjustably mounted to the common frame, in a manner known in the art.

Common frame 10 is configured to be selectively coupled to one of cushion components 15, 20 and to one of elbow components 25, 30. Cushion components 15, 20 differ in at least one respect such that one may be more optimal or preferable for use with one user, while another may be more suitable or preferably for use with another user. For example, cushion component 15 may be an Activa™ component, while cushion component 20 may be an UltraMirage™ Series II cushion component, both available from ResMed. These cushion components can be significantly different from one another, e.g., the Activa™ includes a gusset portion 80 and a cushion clip assembly (not shown) which is not incorporated in the UltraMirage™ cushion design.

Common frame 10 is also configured for use with either elbow component 25, or elbow component 30. Elbow components differ in at least one respect, e.g., each may include gas washout vents that are configured for predetermined washout rates, noise, etc.

Common frame 10 is advantageous since it works with a plurality of different cushion components, elbow components, forehead supports, etc., thereby eliminating the need to specifically make the frame for a particular peripheral component, as is the standard.

2.0 Second Embodiment—Common SWIFT™ Frame with VISTA™ Cushion Component—Below the Nose

FIGS. 2-13 show a mask system 90 according to another embodiment of the present invention. As shown in FIG. 2, mask system 90 includes a common frame 95, a cushion component 100 and a common headgear assembly 105.

Common frame is similar to ResMed's SWIFT™ frame, described in more detail in relation to U.S. patent application Ser. No. 10/781,929, filed Feb. 20, 2004, incorporated herein by reference in its entirety. As shown in FIG. 3, common frame includes a main body 110 including two lateral connectors 115. Each lateral connector 115 is provided with a seal portion 120 (FIG. 4). Each seal portion 120 has a channel 125 structured to receive and support a ring shaped portion 130 of a yoke 135 of the headgear assembly 105. Each seal portion 120 also includes an aperture 140 to receive either an elbow 145 or a plug 150. In an alternative, each seal portion 120 may receive an elbow 145, i.e., receive two sources of gas (without the plug).

FIG. 3 is an exploded view of cushion component 100, frame 95 and a clip element 175, together defining a cushion sub-assembly 155. FIG. 4 shows the cushion sub-assembly 155 in the assembled condition, along with yoke 135, seal portion 120 and elbow 145. FIG. 5 is a cross sectional view of the assembly. FIGS. 6-10 are additional views of the cushion assembly as assembled with lateral headgear straps and associated yokes.

Cushion component 100 includes lateral sides 160 configured to engage with corresponding channels 165 formed in the frame 95. Cushion component 100 includes an aperture 196 (schematically illustrated) to receive the user's nose. End portions 170 of cushion component 100 are wrapped around frame 95, and clip element 175 is attached to the sub-assembly of the cushion component and the frame, by sliding the clip element over the combined cushion component and frame. FIGS. 4 and 13 are a cross-sectional view showing the sandwich-like connection between the lateral sides of the cushion 170, the frame 95 and the clip element 175.

FIG. 11 is a top view of the mask assembly in use on a user's head, while FIG. 12 is a front view. As seen, common frame 95 is positioned just below and partially under the user's nose, and above the upper lip of the user. This positioning of the frame to cushion interface closer to the centroid of the mask assembly, which helps keep a low profile (non-obstructive) and reduces moments imposed on the mask assembly tending to pull the mask assembly away from the user's face.

In the embodiment described above, the cushion component 100 is bisected (see FIGS. 4 and 13) along the longitudinal axis of the frame to create later sides that wrap around the frame for insertion of the channel. In another embodiment, the cushion is not necessarily bisected. Instead, the apertures 162 in the lateral sides of the cushion are simply stretched over the connectors of the frame until a protruding portion of the cushion engages the respective channels of the frame.

Further, cushion component 100 has an upper portion 200 that is configured to contact the transition between the bony and cartilage portions of the user's nose. Generally, with regard to its footprint, the cushion component is similar to ResMed's VISTA™ cushion, as described in U.S. patent application Ser. No. 11/124,251, filed May 9, 2005, incorporated herein by reference.

Cushion component 100 has a thickened portion 205 that acts as a pseudo or “soft” frame to provide support for the rest of the membrane of the cushion. Effectively, the thickened portion 205 of the cushion enlarges the “frame” area of the common Swift™ frame. In this example, the thickened portion 205 has the shape of a semi-circle or trapezoid. See, e.g., FIGS. 2 and 12.

Common headgear assembly 105 is similar to the headgear assembly described in relation to ResMed's U.S. patent application Ser. No. 10/781,929. However, common headgear 105 has some differences. For example, as shown in FIG. 13, the vectors of the headgear straps 210 are changed.

In FIGS. 6-13, the elbow 145 is omitted for clarity, although the plug 150 is illustrated. As shown in FIGS. 3, 7-8, and 11, the mask assembly includes a gas washout vent 215. The vent 215 could be on the frame and/or the cushion component. As shown in FIG. 8, the yoke 130 includes an alignment indicator 220 that aligns with one of a corresponding array of indicators 225 on the cushion/frame subassembly. The cushion/frame subassembly is rotatable relative to the headgear to ensure proper fit.

3.0 Third Embodiment—Common Swift™ Frame with Mirage™ Cushion Component

FIG. 14 illustrates a mask assembly 230 include a common frame 235, a headgear assembly 240 and a cushion component 245. This embodiment is similar to the prior embodiment, especially as the common frame is the same as described above in relation to FIGS. 2-13. The main difference is that the cushion component 245 takes the form of a nasal mask, e.g., ResMed's Mirage™ type cushion, as described in U.S. Pat. No. 6,112,746, incorporated herein by reference in its entirety. In this embodiment, the cushion component 245 is configured to form a breathing cavity that surrounds the nose of the user. The cushion component includes an upper apex portion 250 that makes contact with the bridge of the user's nose, between the eyes.

The cushion component 250 may include a thickened section 255 in order to help prevent flopping of the cushion away from the user's face. The thickened section 255 may include a cutout 260 in each corner to reduce force on the nasal bridge region.

4.0 Fourth Embodiment—Common Swift™ Frame with Vista™ Cushion Component—Over the Nose

FIGS. 15-16 show a mask assembly 275 according to another embodiment of the present invention. Mask assembly 275 includes a common frame 280, a headgear assembly 285, and a cushion component 290 like that described in relation to FIGS. 2-13 above. One difference in the present embodiment is the positioning of the common frame 280 relative to the user's face/nose. Specifically, the common frame 280 is positioned above the lower portion of the user's nose, such that the tip of the nose extends below the clip element 295. Further, as shown in FIG. 16, the vectors formed by the headgear straps 300 are slightly different than as shown in described in relation to FIG. 13. As a result of the positioning of the frame/cushion interface to more centrally locate the frame relative to the cushion, and/or because the vectors from the headgear straps act closer to the centroid of the mask on the face, this design may not necessarily include a thickened portion of the cushion.

5.0 Fifth Embodiment—Vista/Swift Prongs Combination

FIGS. 17-19 show a portion of another mask assembly 305 according to an embodiment of the present invention. FIG. 17 shows a common Swift™ frame and cushion assembly 310 in isolation, including prong elements 315 for engagement with the user's nares. FIG. 18 shows a supplemental Vista™ style cushion 320 adapted for use with the Swift™ cushion/frame assembly 310. The mask assembly is supported on the user's head using a headgear assembly as described above.

The supplemental cushion 320 includes at least one hole 325 provided on its lateral side for insertion over the frame/cushion assembly 310. Supplemental cushion 320 also includes a centrally located hole 330 that aligns with the gas washout vents 335 of the frame/cushion assembly 310. FIG. 19 shows the frame/cushion assembly 310 and the supplemental cushion 320 in assembled form.

To assemble the supplemental cushion over the frame, each hole 325 of the supplemental cushion 320 is stretched over the connector of the frame, and the resiliency of the material of the supplemental cushion allows it to engage with the channels of the frame and/or to simply seal with an exposed surface of the frame cushion assembly. In this position, the prongs 315 seal with the nares, while the supplemental cushion includes a face contacting portion that seals with the user' face.

6.0 Additional Embodiments

As can be determined from the description above in relation to the embodiments of FIGS. 2-13 and the embodiment of FIGS. 15-16, one aspect of the invention is directed to the combination of a Swift™ frame with a Vista™ cushion component. As can be appreciated, the combination of these dissimilar mask systems required a number of adjustments, as can be derived from the above description and the drawings.

6.1 Locked Elbow

Furthermore, there are additional factors that may be considered when combining the various mask systems. For example, the force due to air pressure against the cushion may cause moments about the elbow. If these moments are not counteracted, the result may be the cushion rotating and losing seal. The elbow should be stiff enough to prevent rotation under pressure. A locking or ratcheting mechanism may be implemented to lock the rotation on the elbow when the desired angle is found. Locking may be achieved using an interference fit, and/or locking components, such as detents or a pin/groove arrangement. Generally, an approximation of the desired effect can be achieved by simply fixing the elbow in place relative to the frame. Otherwise, simply inhibiting rotation, e.g., by strapping the elbow to the adjacent headgear, can be effective as well.

6.2 Stiffening Member For Cushion Component

When the cushion is under pressure, moments about the cushion to frame interface are created. The force vector points which cause the moments may be shifted by introducing a non-flexible or stiffening member to the cushion. That is to say, in addition to having a moment about the elbow, there is also a moment about the interface of the stiff section of the cushion and the flexible part of the cushion.

6.2.1 Stiffening Ribs

The mask assembly 340 in FIG. 20 includes a cushion component 345 that is similar in general shape to the Vista™ cushion in terms of its intended sealing footprint relative to the user's face, but it includes a plurality of ribs 350 that extend from the clip element 355 to the top of the cushion, to stop or help prevent the cushion from flexing about the elbow (or flopping off the face). The stiffening member (ribs in this example) will move this vector away from the elbow, and prevent the cushion from flopping off the face. The stiffening member should extend as close to the skin as possible without compromising comfort. The common frame is similar to that described above and may be, e.g., a Swift™ frame.

The mask assembly 360 in FIG. 21 includes a rib 365 along the perimeter of the cushion to help support and/or push the cushion onto the user's face. The rib 365 may be comolded with the cushion. The cushion forms a breathing cavity which receives the nose of the user, and the upper apex of the cushion extends across the bridge of the user, between the eyes. In this example, the cushion can be ResMed's Mirage™ cushion, adapted for assembly to common frame. Common frame is similar to that described above and may be, e.g., a Swift™ frame. However, the clip element 370 of the cushion assembly is slightly rotated such that it is positioned to face downwardly.

6.2.2 Thickened Cushion Portion

The stiffening member may take the form of one or more thickened elements, e.g., by thickening the cushion which will result in it being stiffer in sections. See, e.g., the relatively thickened portion of cushion component in FIG. 13. Ribs could be made in the cushions, extending from the frame to the highest point of the cushion. A pseudo frame could be implemented where a large portion of the cushion is thick silicone, only the areas in contact, or requiring flex (as in a “bubble” cushion or single walled membrane) will be thin.

6.3 Nose Tip Cushion Component

FIG. 22 shows a mask assembly 380 according to another embodiment of the invention having a headgear assembly 385 and a common Swift™ frame 390 as described above, as well as cushion component 395 in the form of a nose tip cushion. The cushion includes a membrane that extends up the side of the nose. The membrane could extend just over the tip of the nose. The cushion could incorporate a bubble style seal over the tip of the nose. The mask assembly includes one or more vent openings 400 provided in the frame/cushion component.

6.4 Full-Face Cushion

FIG. 23 shows a mask assembly 405 according to yet another embodiment of the present invention having a headgear assembly 410 and common Swift™ frame 415 as described above, as well as a cushion component 420 in the form of a full-face cushion, such as that available from ResMed under the name UltraMirage™ full-face cushion and described in U.S. Pat. No. 6,513,526, incorporated herein by reference in its entirety. The cushion component 420 would be adapted for use with a Swift™ type frame, as described above.

The cushion 420 may include a rib 425 that extends from the bottom to the top of the cushion. Furthermore, the frame 415 is positioned on the upper ½ to upper ⅓ of the cushion to support the cushion. The frame to cushion interface is positioned below the nose, although it may be above the nose. The cushion may include one or more gas washout vents 430.

7.0 Adjustable Positioning of the Cushion 7.1 Adjustable Nose Height

FIG. 24 shows a mask assembly 440 according to yet another embodiment of the present invention including a common Swift™ frame 445, a headgear assembly 450, and a Vista™-like cushion 455 supported by the frame.

The upper part 460 of the cushion may include a thin membrane (the lower cushion may be like a double wall Vista™ cushion). This has the advantage of reduced weight and subjectively feels light to wear. It may also allow deflection around contours of nose as it will be more flexible than a conventional thick cushion. This will help with fit and the range of patients suited to each size.

In an alternative, the upper part 460 of the cushion shown in FIG. 24 includes a bellows type arrangement around the cushion which may be inflated to help pressure and fit, like the ResMed Activa™ mask, described in U.S. Pat. No. 4,772,760 and U.S. application Ser. No. 10/655,622, filed Sep. 5, 2003, each incorporated herein by reference in its entirety. In the alternative, the cushion may include a stiff drinking straw-like structure, e.g., plastic corrugations that maintain shape in a variety of positions. The straw-like structure would click or fold into different positions to allow more or less nose height.

The lower part of the cushion 465 may include a gusset portion, a double gusset, or a solid silicon structure.

7.2 Adjustable Cushion Height

As described above, the position of the centroid of the cushion to frame interface (frame clip location) may be changed, depending on application. The closer the headgear vectors act to the centroid of the cushion the more stable the cushion will be on the face of the patient; this can reduce the rigidity required within the cushion to maintain support of the membrane. The frame location in FIGS. 2-13 is closer to the centroid as compared to the location of the centroid in FIGS. 15-16. In these embodiments, the positions of the cushions relative to the face remain generally constant.

However, it is also possible to change the position of the cushion relative to the face and frame, while maintaining the frame in a constant position. The mask assembly 500 in FIGS. 25 -26 includes a common Swift™ frame 505 supported by Swift™-like headgear 510, in addition to a Vista™ like cushion 515 supported by the frame 505.

In FIGS. 25-26, the axis of location of the frame 505 is across the middle of the nose, although it could be higher or lower. As schematically shown, the axis of location of the frame onto the cushion may vary according to user preference (which will be influenced by head shape/headgear angles). In FIGS. 25-26, it can be seen that the headgear-frame angle remains constant and the frame is located at higher or lower cushion positions, position 2 in FIG. 25 and position 3 in FIG. 26. Adjustment can be effected using mechanical expedients such as a sliding arrangement. Holes in the sides of the cushion may allow stretching in to accommodate positioning of the cushion in the various positions.

Alternatively, the headgear and frame angle may rotate around the same cushion position. As a further alternative the headgear location point could be on a lobe or cam to move it relative to the cushion. A further embodiment is the use of weight to change the center of gravity of the cushion or frame/headgear system.

8.0 Chin Strap

FIGS. 27-31 illustrate a mask assembly 600 according to a further embodiment of the present invention. Mask assembly includes a frame 605 (e.g. polycarbonate shell), a headgear assembly 610, a cushion component 615, and a chin strap assembly 620 supported by the frame.

Chin strap assembly 620 includes an extender 625 and chin strap 630. Extender 625 is shown in FIG. 30 and is preferably made of a rigid material, e.g., polycarbonate or a rigid plastic backed with headgear foam material. Extender 625 includes an aperture 635 by which a bevel clip 640 (FIG. 29) may be used to selectively attach the extender 625 to the frame, e.g., using interference snap fit. Extender 625 includes a hole 640 for receiving a strap 645 of the chin strap. Each strap includes hook and loop fastening elements, e.g., Velcro®.

Chin strap 630 includes a cushion sealing area 650, and is made from a foamed headgear material. The chin strap is preferably elastic. Chin strap is bonded to the frame at a bond point or region 655, e.g., as shown in FIGS. 27, 28 and 31. Bonding may be achieved, e.g., via adhesive, plasma or lamination methods.

Another variant is to simply use only the extender and chin strap shown in FIGS. 30 and 31, respectively, along with another mask of choice, e.g., ResMed's Nightingale mask, more fully described in PCT Patent application no. PCT/AU04/01832, filed Dec. 24, 2004, incorporated by reference in its entirety. A further embodiment is the use of the Nightingale headgear with the chin strap assembly and the frame cushion.

A further embodiment is the combination the full-face seal as shown in FIG. 27, along with nasal prongs as shown in FIG. 19.

While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, barriatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications. 

1.-20. (canceled)
 21. A respiratory mask assembly for providing respiratory therapy to a patient, the respiratory mask assembly comprising: a main body; a cushion component including a sealing portion, wherein the sealing portion is constructed and arranged to form a seal with a patient's nose; a cushion retainer configured to releasably couple the cushion component to the main body, wherein the cushion retainer is relatively harder than the cushion component, wherein the cushion retainer includes a cushion retainer part structured and arranged to engage behind a retainer part provided to the main body to releasably couple the cushion retainer to the main body, wherein the cushion component and the cushion retainer form at least a portion of a breathing chamber pressurizable to a therapeutic pressure, wherein the cushion retainer includes an opening structured to receive a flow of air at the therapeutic pressure for breathing by the patient, and wherein the cushion retainer is configured to releasably couple the cushion component to the main body while allowing the flow of air to the cushion component; a gas washout vent configured to releasably couple with the main body, the gas washout vent configured to washout gas from the breathing chamber to ambient atmosphere; headgear to maintain the respiratory mask assembly in position on a patient's head, the headgear including upper side straps and lower side straps; and a pair of lower headgear connectors, each of the pair of lower headgear connectors configured to connect a respective one of the lower side straps to the main body.
 22. The respiratory mask assembly according to claim 21, further comprising a pair of upper lateral members provided to the main body, each of the pair of upper lateral members including a respective one of a pair of upper headgear connectors, and the upper side straps are adapted to connect to a respective of the pair of upper headgear connectors.
 23. The respiratory mask assembly according to claim 21, wherein the main body includes a lower opening having a closed shape and an upper opening having a closed shape that is spaced apart and superior to the lower opening.
 24. The respiratory mask assembly according to claim 23, wherein the lower opening is configured to communicate with the gas washout vent when the gas washout vent is releasably coupled with the main body.
 25. The respiratory mask assembly according to claim 23, wherein the upper opening is configured to receive the cushion retainer when the cushion retainer is releasably coupled with the main body.
 26. The respiratory mask assembly according to claim 21, wherein the cushion retainer includes an inside surface exposed to said therapeutic pressure in use.
 27. The respiratory mask assembly according to claim 21, further comprising an elbow structured to connect to a respiratory gas conduit to deliver the flow of air at the therapeutic pressure to the breathing chamber.
 28. The respiratory mask assembly according to claim 21, wherein the cushion retainer comprises polycarbonate and the cushion component comprises silicone.
 29. The respiratory mask assembly according to claim 21, wherein the cushion retainer part forms a space to receive the retainer part of the main body when the cushion retainer is releasably coupled with the main body.
 30. A CPAP system for providing respiratory therapy to a patient, the CPAP system comprising: the respiratory mask assembly according to claim 21; a blower to supply a flow of air at a therapeutic pressure; and a conduit to pass the flow of air at the therapeutic pressure from the blower to the respiratory mask assembly.
 31. A respiratory mask assembly for providing respiratory therapy to a patient, the respiratory mask assembly comprising: a main body including lateral sides, each of the lateral sides of the main body including an opening structured to receive a flow of air at a therapeutic pressure for breathing by the patient; a cushion component including a sealing portion, wherein the sealing portion is constructed and arranged to form a seal with a patient's nose; a cushion retainer configured to releasably couple the cushion component to the main body; headgear to maintain the respiratory mask assembly in position on a patient's head, the headgear including side straps; a pair of inlet conduits structured to deliver breathable gas into the respiratory mask assembly for breathing by the patient, each of the pair of inlet conduits provided to a respective one of the lateral sides of the main body; and a pair of connectors configured to releasably couple the pair of inlet conduits to a respective opening of the main body.
 32. The respiratory mask assembly according to claim 31, wherein the cushion retainer is in the form of a clip element.
 33. The respiratory mask assembly according to claim 31, wherein the cushion retainer includes a cushion retainer part structured and arranged to engage behind a retainer part provided to the main body to releasably couple the cushion retainer to the main body.
 34. The respiratory mask assembly according to claim 31, wherein the side straps are connected to a respective one of a pair of headgear connectors, each of the pair of headgear connectors provided to a respective one of the pair of connectors.
 35. The respiratory mask assembly according to claim 31, further comprising a gas washout vent provided to the main body for washout gas.
 36. A CPAP system for providing respiratory therapy to a patient, the CPAP system comprising: the respiratory mask assembly according to claim 31; a blower to supply a flow of air at a therapeutic pressure; and a conduit to pass the flow of air at the therapeutic pressure from the blower to the respiratory mask assembly. 